The most commonly used automotive vehicle differential is of the bevel gear configuration. This differential is coupled to the vehicle engine drive shaft and divides the engine's output and torque equally to both drive wheel axles. This differential permits the speeds of the driven shafts to change according to demand.
The conventional differential does not permit any larger amount of torque to be transmitted to the ground that twice the amount that may be transmitted to the wheel with the lesser traction. Consequently, when the traction of either wheel is zero, such as when the wheel is spinning on ice, there is no power or torque transmitted to the ground by either of the wheels or driven axles. As is well known, when one wheel spins, the opposite wheel does not rotate at all with this conventional differential.
Consequently, various types of power-dividing or limited slip differentials have been developed for the purpose of powering one wheel when the opposite wheel spins, i.e., has lost traction. By way of example only, one form of such a power-dividing differential is disclosed in my prior U.S. Pat. No. 2,720,796 issued Jan. 18, 1955.
However, available limited slip power-dividing differentials are relatively expensive and complex in construction and tend to wear out sooner than the above conventional differential. Moreover, they typically do not perform satisfactorily at low ground friction when the vehicle goes around a curve where the outer wheel must rotate faster than the inner wheel, in which cases, there is a tendency to lose control due to lock up of wheels causing scuffing of the tires. Further, problems tend to arise when a wheel momentarily leaves the ground while the other remains in contact with the ground. Further, when one wheel looses traction, there is still a tendency for it to spin to some extent. Consequently, there has been a need for an improved differential capable of instantaneously transmitting torque to the wheel having traction while the other wheel looses its traction and also to handle the problem of one wheel rotating faster than the other, without further complicating or increasing the cost of the differential and preferably reducing same.